Metal roofing systems and the flashings used therewith, as well as the installing thereof, are very well known in the art. Indeed, as better shown in FIG. 1, it is customary to use metal flashings on the perimeter of a roof surface to reinforce and protect the same against wind damage and uplift, as well as to use flashings on roof edges and the transitions thereof to protect the same against water infiltration, for example. The flashings are generally supplied by the manufacturer of the roofing system, but can also be formed on site by the installers of the roofing system in order to adapt the flashings to the specific roofing situation at hand.
It is also well known in the art that over the years, flashing structures have evolved, partly driven by the economics of installation costs, partly driven by esthetic concerns, but mostly driven as a result and in response to failures of previous flashing structures, either due to wind damage and/or water infiltration, for example.
Known in the art are three main ways that a panel or shingle may be joined to a piece of flashing. Briefly explained, these three ways are the following: a) a folded shingle or panel over a lip of a flashing, as better shown in FIG. 2: b) the insertion of a shingle or panel into a groove or open lock in a flashing, as better shown in FIG. 3; and c) the insertion of a shingle or panel into a thin groove or slip-lock in a flashing, as better shown in FIG. 4.
Indeed, it is already common practice to create a first drainage channel or “gutter” on the flashing by adding a return bend (for example, a 180 degree bend), at the end of the flashing, underneath the shingle or flashing secured thereon, as better shown in FIGS. 3 and 4. This return bend is intended to prevent water in the gutter from moving from the flashing surface and onto the roof. However, this method is not fool-proof with the slip-lock type flashing shown in FIG. 4, for example, as debris often builds up in the crevice and the gutter, and consequently can cause blockage of the gutter and this result in the deflection of water onto the roof surface, which is very undesirable for obvious reasons.
The first two methods shown in FIGS. 2 and 3 are fairly reliable but require care and expertise by an installer in order to be properly performed. Namely, for the flashing illustrated in FIG. 2, the installer must trim the shingle or panel to typically provide an “overhang” of about 1.5 to 3 cm, which is then hand-bent over the lip and crimped, resulting in a fairly strong and relatively water-proof joint. When properly done, it results in a substantial even and clean appearance, and a fairly secure attachment to the supporting flashing. However, this type of flashing requires extensive training, experience and care from an installer in order to be properly installed, and thus may not be readily installed by a “do-it-yourself” person.
The flashing structure shown in FIG. 3 requires the shingle or panel to be inserted into an open lock channel, and trimmed in such a way that the shingle generally has a 90 degree bend, typically with a 1.5 to 2 cm riser, which then fills up the vertical gap, and touches the back of the open lock channel. Done properly, this type of flashing makes it very difficult for water to work its way around the riser and into the gutter. However, it has been found in the art that many installers do not take care to measure the riser properly, and/or inadvertently improperly measure the same, resulting in that the riser on the shingle is often too short and far from the back of the channel, thus allowing the water to easily move past the riser and into the channel, which is also very undesirable for obvious reasons.
The flashing structure of FIG. 4 is easier for an installer to install as it involves trimming the shingle so that it fits under the securing lip of the flashing, but often fails due to water infiltration as described in the preceding paragraph. This type of flashing is used by a number of manufacturers who claim that anyone with little or no roofing experience can install the system, but end up having to face frequent complaints by customers in regards to leakage, resulting from design and installation flaws of this type of flashing structure.
It is also known in the art that another issue that effects the integrity of a roofing installation is that the installers often do not measure carefully the amount of penetration of the shingle under the slip-lock of the flashing, with the result that some shingles that are “rough-trimmed” have very little material under the slip-lock. As a result thereof, in winter typically, when cold weathers cause contraction of the metal shingles, the shingles may pop out of the slip-lock, as well as be damaged by wind, snow, and/or ice, which is also very undesirable. In worst cases, such loose shingles may be blown away or swept off the roof surface and therefore result in severe damages to the roofing system, resulting in water infiltration and/or poor covering of the roof structure
Also known in the art is the use of a valley flashing Which is typically used to protect the valleys of a roof, that is, two adjoining roof sections meeting on a slope. These valleys present the most amount of potential problems as this is where the water is typically concentrated, and where ice and/or snow can accumulate. Debris such as leaves, pine needles, and the like, often accumulate in these valleys and may cause water flowing off the roof to be diverted off course, thus resulting in leaks. The traditional practice in metal roofing has been to use “open” valleys, with built-in lips along both sides of the valleys to provide anchoring points and water deflection points for securing the shingles and/or flashings. However, to secure the shingles and/or panels to the valley in this manner requires extensive skill, specialized equipment and substantial time, thus resulting in considerable installation costs. Furthermore, it has been found in the art that many installers often try to “cut corners” and thus produce an end result which often leaks, which is also very undesirable.
Some companies have used “closed” valleys, which incorporate the slip-lock method of fastening the shingles, to speed up the installation, but they accumulate debris in the narrow junction between the shingles/panels and the lips of the flashing, and in winter they also ice up, causing water to overflow the drainage gutter and thus cause a leak, which is undesirable
There are also valley flashing designs in existence which try to deal with the potential blockage of the pockets holding the ends of the shingles with a drainage system that directs the water to a central channel. These designs are typically of a two-piece construction, and the upper piece can be dislodged by the pressure and movement of ice and/or snow on the roof, causing the pocket holding the shingles to be lost.
Also known in the art are several documents describing different types of roofing systems and the flashing structures used therewith. Indeed, known to the Applicant are the following U.S. patent: U.S. Pat. No. 3,024,573 (McKinley); U.S. Pat. No. 3,264,790 (Beals); U.S. Pat. No. 3,680,269 (Fischer, Jr. et al.); U.S. Pat. No. 4,071,987 (Hickman); U.S. Pat. No. 4,241,549 (Hall, III et al.); U.S. Pat. No. 4,403,458 (Lolley); U.S. Pat. No. 4,592,176 (van Herpen); U.S. Pat. No. 4,598,507 (Hickman) U.S. Pat. No. 4,780,999 (Webb et al.); U.S. Pat. No. 4,858,406 (Lane et al.); U.S. Pat. No. 5,115,603 (Blair); U.S. Pat. No. 5,927,023 (Kittilstad); and U.S. Pat. No. 5,960,591 (Schlüter).
However, none of the above-mentioned documents seems to teach, illustrate or even suggest a flashing structure which overcomes the above-discussed prior art problems.
Hence, in light of the aforementioned, there is a need for an improved flashing structure which, by virtue of its design and components, would overcome some of the aforementioned problems.